1. Field of the Invention
The present invention relates to a device for use in copying machines and the like for treating toner images to improve the quality of the images.
2. Description of the Prior Art
As already known, electrophotographic copying machines are adapted to form a toner image on a copy sheet by an electrophotographic process and thereafter fix the toner image to the copy sheet by fusing with heat fixing means. The fixed toner image has surface irregularities, which nevertheless produce no adverse effect insofar as the toner used is black as is usually the case. However, with various color toners introduced into use recently, such irregularities pose a problem. The color toner, when used, fails to produce distinct images since light is scattered by the surface irregularities of the toner image. Especially when a color toner image formed on a transparent sheet is projected by an overhead projector (hereinafter referred to as "OHP"), the light from the light source of the OHP is scattered considerably by the surface irregularities of the color toner image, with the result that the color of the projected image appears darker than the true color of the original. Accordingly, it has been proposed to cover the irregular surface of the toner image with a transparent auxiliary material to smooth the surface so that the original color can be reproduced as desired for use with the OHP and the like (Unexamined Japanese Patent Publication No. SHO 60-135974).
Unexamined Japanese Patent Publication No. SHO 59184382 proposes a coating device for applying a transparent resin to the fixed toner images on copy sheets for OHPs, and a dryer disposed downstream from the device for drying the transparent resin coating. However, the coating device and the dryer needed render the machine large-sized and complex.